weird sound from engine

[stefan34]

I have an atc250r 83 and I have just repared the rear axle (new bearings) and put in a smaller main jet. and it al ran fine expect I keep hearing a vibrating sound from the engine (like a srew is losen) but it stil runs fine.
when i give more gas the sound gets harder I wil post a video with the sound later one.


enyone now's what it is

I have one sugestion mayby the clutch (when i refreshed the oil it did very weird but later on everyting was fine again)

http://video.google.nl/videoplay?docid=-8401588947387304405

[stefan34]

could be I did have put in a new main jet and didn't hade to adjust anything.
but I have an stock plug in it ? and I run 30:1

[atctim]

Crank Bearings maybe? Or maybe piston slap..

take your top end off and inspect.

[stefan34]

yeah I would but a friend of mine sayd it aind the piston maybe bougie so I am going to buy a new bougie and if that dousn't work I wil take the engine apart but that is after my exams so that wil take a wile